BIOS 255 / BIOS255 Exam 1: Anatomy & Physiology III
with Lab Latest update 2026/2027 | Chamberlain |
Q&A with Rationales | Grade A | Pass Guaranteed
A+ Graded
Q1: A patient with type A- blood receives a transfusion of type B+ blood. Which of the following
best describes the expected immunological reaction?
A. No reaction because the Rh factor is compatible
B. Agglutination due to anti-B antibodies in the recipient's plasma [CORRECT]
C. Hemolysis due to anti-A antibodies in the donor's plasma
D. No reaction because the ABO types are compatible
Correct Answer: B
Rationale: Correct because a patient with type A blood has anti-B antibodies in their
plasma. When exposed to type B blood, these antibodies will bind to the B antigens on the
donor's erythrocytes, causing agglutination. This matches the ABO incompatibility reaction
taught in BIOS255.
Q2: Which of the following sequences correctly represents the order of events during hemostasis
following a vascular injury?
A. Fibrin formation → Platelet plug formation → Vascular spasm → Coagulation
B. Vascular spasm → Platelet plug formation → Coagulation (fibrin clot formation)
[CORRECT]
C. Coagulation → Vascular spasm → Platelet plug formation → Fibrinolysis
D. Platelet plug formation → Vascular spasm → Coagulation → Retraction
Correct Answer: B
Rationale: Correct because hemostasis begins with immediate vascular spasm to reduce
blood flow, followed by platelet adhesion and aggregation to form a temporary plug.
Finally, the coagulation cascade is activated to form a stable fibrin clot. This sequence is the
standard physiological response to vascular injury.
,Q3: During the cardiac cycle, the second heart sound (S2) marks the closure of which valves?
A. Atrioventricular (AV) valves
B. Semilunar valves open
C. Aortic and pulmonary valves close [CORRECT]
D. Mitral and tricuspid valves close
Correct Answer: C
Rationale: Correct because S2 is produced by the closure of the aortic and pulmonary
semilunar valves at the beginning of ventricular diastole. This matches the standard heart
sound physiology taught in BIOS255, where S1 is AV closure and S2 is semilunar closure.
Q4: A healthy adult has a heart rate of 75 beats per minute and a stroke volume of 70 mL/beat.
What is the cardiac output (CO)?
A. 4.5 L/min
B. 5.25 L/min [CORRECT]
C. 6.0 L/min
D. 5250 mL/beat
Correct Answer: B
Rationale: Correct because Cardiac Output (CO) is calculated by the formula CO = Heart
Rate (HR) × Stroke Volume (SV). 75 beats/min × 70 mL/beat = 5250 mL/min, which
converts to 5.25 L/min. This calculation is fundamental to hemodynamics in BIOS255.
Q5: Which of the following structures is responsible for initiating the electrical impulse in a
normal, healthy heart?
A. Atrioventricular (AV) node
B. Bundle of His
C. Sinoatrial (SA) node [CORRECT]
D. Purkinje fibers
Correct Answer: C
Rationale: Correct because the SA node is the primary pacemaker of the heart, located in
the right atrium. It spontaneously depolarizes to initiate the action potential that spreads
through the heart, triggering contraction. This is the starting point of the intrinsic
conduction system.
, Q6: Select all that apply: Which of the following are functions of the respiratory system?
A. Regulation of blood pH [CORRECT]
B. Production of erythropoietin
C. Protection against pathogens [CORRECT]
D. Synthesis of vitamin D
E. Voice production [CORRECT]
Correct Answer: A, C, E
Rationale: Correct because the respiratory system regulates blood pH by controlling CO2
levels (A), protects against inhaled pathogens via mucus and cilia (C), and allows for voice
production through the larynx (E). Erythropoietin is produced by the kidneys (B), and
vitamin D synthesis occurs in the skin (D).
Q7: Which layer of a blood vessel is composed primarily of smooth muscle and is responsible
for vasoconstriction and vasodilation?
A. Tunica intima
B. Tunica media [CORRECT]
C. Tunica externa (adventitia)
D. Endothelium
Correct Answer: B
Rationale: Correct because the tunica media is the middle layer of blood vessels, composed
mainly of smooth muscle and elastic fibers. Contraction and relaxation of this smooth
muscle layer control the diameter of the vessel, regulating blood flow and pressure.
Q8: A patient presents with a heart rate of 180 bpm. The ECG shows absent P waves and a
"sawtooth" pattern in lead II. What is the most likely interpretation?
A. Sinus tachycardia
B. Atrial fibrillation
C. Atrial flutter [CORRECT]
D. Ventricular tachycardia
Correct Answer: C
Rationale: Correct because atrial flutter is characterized by a rapid, regular atrial rate
(often 250-350 bpm) with a characteristic "sawtooth" pattern of F waves on the ECG. The
ventricular rate is often a fraction of the atrial rate (e.g., 2:1 block resulting in 150 bpm, or
variable block). Absent P waves and sawtooth pattern are classic signs.
with Lab Latest update 2026/2027 | Chamberlain |
Q&A with Rationales | Grade A | Pass Guaranteed
A+ Graded
Q1: A patient with type A- blood receives a transfusion of type B+ blood. Which of the following
best describes the expected immunological reaction?
A. No reaction because the Rh factor is compatible
B. Agglutination due to anti-B antibodies in the recipient's plasma [CORRECT]
C. Hemolysis due to anti-A antibodies in the donor's plasma
D. No reaction because the ABO types are compatible
Correct Answer: B
Rationale: Correct because a patient with type A blood has anti-B antibodies in their
plasma. When exposed to type B blood, these antibodies will bind to the B antigens on the
donor's erythrocytes, causing agglutination. This matches the ABO incompatibility reaction
taught in BIOS255.
Q2: Which of the following sequences correctly represents the order of events during hemostasis
following a vascular injury?
A. Fibrin formation → Platelet plug formation → Vascular spasm → Coagulation
B. Vascular spasm → Platelet plug formation → Coagulation (fibrin clot formation)
[CORRECT]
C. Coagulation → Vascular spasm → Platelet plug formation → Fibrinolysis
D. Platelet plug formation → Vascular spasm → Coagulation → Retraction
Correct Answer: B
Rationale: Correct because hemostasis begins with immediate vascular spasm to reduce
blood flow, followed by platelet adhesion and aggregation to form a temporary plug.
Finally, the coagulation cascade is activated to form a stable fibrin clot. This sequence is the
standard physiological response to vascular injury.
,Q3: During the cardiac cycle, the second heart sound (S2) marks the closure of which valves?
A. Atrioventricular (AV) valves
B. Semilunar valves open
C. Aortic and pulmonary valves close [CORRECT]
D. Mitral and tricuspid valves close
Correct Answer: C
Rationale: Correct because S2 is produced by the closure of the aortic and pulmonary
semilunar valves at the beginning of ventricular diastole. This matches the standard heart
sound physiology taught in BIOS255, where S1 is AV closure and S2 is semilunar closure.
Q4: A healthy adult has a heart rate of 75 beats per minute and a stroke volume of 70 mL/beat.
What is the cardiac output (CO)?
A. 4.5 L/min
B. 5.25 L/min [CORRECT]
C. 6.0 L/min
D. 5250 mL/beat
Correct Answer: B
Rationale: Correct because Cardiac Output (CO) is calculated by the formula CO = Heart
Rate (HR) × Stroke Volume (SV). 75 beats/min × 70 mL/beat = 5250 mL/min, which
converts to 5.25 L/min. This calculation is fundamental to hemodynamics in BIOS255.
Q5: Which of the following structures is responsible for initiating the electrical impulse in a
normal, healthy heart?
A. Atrioventricular (AV) node
B. Bundle of His
C. Sinoatrial (SA) node [CORRECT]
D. Purkinje fibers
Correct Answer: C
Rationale: Correct because the SA node is the primary pacemaker of the heart, located in
the right atrium. It spontaneously depolarizes to initiate the action potential that spreads
through the heart, triggering contraction. This is the starting point of the intrinsic
conduction system.
, Q6: Select all that apply: Which of the following are functions of the respiratory system?
A. Regulation of blood pH [CORRECT]
B. Production of erythropoietin
C. Protection against pathogens [CORRECT]
D. Synthesis of vitamin D
E. Voice production [CORRECT]
Correct Answer: A, C, E
Rationale: Correct because the respiratory system regulates blood pH by controlling CO2
levels (A), protects against inhaled pathogens via mucus and cilia (C), and allows for voice
production through the larynx (E). Erythropoietin is produced by the kidneys (B), and
vitamin D synthesis occurs in the skin (D).
Q7: Which layer of a blood vessel is composed primarily of smooth muscle and is responsible
for vasoconstriction and vasodilation?
A. Tunica intima
B. Tunica media [CORRECT]
C. Tunica externa (adventitia)
D. Endothelium
Correct Answer: B
Rationale: Correct because the tunica media is the middle layer of blood vessels, composed
mainly of smooth muscle and elastic fibers. Contraction and relaxation of this smooth
muscle layer control the diameter of the vessel, regulating blood flow and pressure.
Q8: A patient presents with a heart rate of 180 bpm. The ECG shows absent P waves and a
"sawtooth" pattern in lead II. What is the most likely interpretation?
A. Sinus tachycardia
B. Atrial fibrillation
C. Atrial flutter [CORRECT]
D. Ventricular tachycardia
Correct Answer: C
Rationale: Correct because atrial flutter is characterized by a rapid, regular atrial rate
(often 250-350 bpm) with a characteristic "sawtooth" pattern of F waves on the ECG. The
ventricular rate is often a fraction of the atrial rate (e.g., 2:1 block resulting in 150 bpm, or
variable block). Absent P waves and sawtooth pattern are classic signs.
